Is it important to update to v8.7.1 or can I stick with v8.7.1 bottom line:

Always update. You know that by now.

Cliffsnotes of this update?

An important bug exists in 8.7.0 and it can give you the impression that the ship mouse interface does not activate if the ship is too close to the bottom edge of the map – and then you can no longer activate any ship (in reality, the interface is far offscreen and can’t be closed/manipulated. oops!). 8.7.1’s sole purpose is to fix this mistake of 8.7.0 released yesterday on July 11th.